喺邊度買casio手錶多款&平?

There is a showroom of Casio Watches in Tsim Sha Tsui, there are many many G-shock. But, the price is a little bit higher than other shops because the showroom charges the original price. The address is at

Shop G12, Mirror Tower,
61 Mody Road, Tsim Sha Tsui East
(Opposite to KLN Shangri-La Hotel)

If you want some common G-shock models and lower price, you can go to Lucky Plaza in Shatin. There are many watch shops!

方形膠裱 eh? Must be the G8000/8100 series.
I don't know the exact pricing info though, but it should cost less than $700.
To check out the extensive lineup please go to Javys showroom in Central or TST (G-factory, Mirror Tower). But if you want the best deals then try NOT to buy from Javys first -- they charge premium prices.
You can try finding better deals at places like Sino or other independent watch stores. One caveat though, when you buy from those stores at Sino you don't get to keep the warranty card so any subsequent repairs you must bring the watch back the watch to that shop first. This is wrong -- as the customer YOU should be keepint the warranty card.
If you want total peace of mind, get the timepiece from a reliable source (Javys, City Chain etc.).